This longitudinal project aims to assess the effect of stress and strain on the physical and instrumental functioning of persons aged 85 and older who live in the community. A sample of 150 (75 men and 75 women) recruited from a variety of non-institutionalized sources will be interviewed every six months over an 18-month period. Unlike other studies that are cross-sectional, this study proposes to measure the process of coping through longitudinal design among the oldest-old and to determine what mediating role psychological characteristics and social supports play in the relationship between stress, functional ability and mortality. Data will be collected by face-to-face, semi-structured, interviews in the respondent's homes at four points, six months apart. The longitudinal design permits analysis of change in function as related to change in stressors, as moderated by coping methods, psychological characteristics, and social supports. The overall objectives of this research are to delineate the coping processes among the oldest-old and to specify the relationships between function and stress while controlling for other factors.